Hands are frequently contaminated with fecal bacteria and enteric pathogens globally: A systematic review and meta-analysis

Abstract

Enteric pathogen infections are a leading cause of morbidity and mortality globally, with the highest disease burden in low-income countries. Hands act as intermediaries in enteric pathogen transmission, transferring enteric pathogens between people and the environment through contact with food, water, and soil. In this study, we conducted a systematic review of prevalence and concentrations of fecal indicator microorganisms (i.e., E. coli, fecal coliform) and enteric pathogens on hands. We identified eighty studies, reporting 31,305 observations of hand contamination of people in community or household settings. The studies investigated 45 unique microorganisms, of which the most commonly reported indicators were E. coli and fecal coliforms. Hand contamination with 14 unique enteric pathogens was reported, with adenovirus and rotavirus as the most frequent. Mean E. coli prevalence on hands was 40% [95% CI 18%-62%] and mean fecal coliform prevalence was 42% [95% CI 16%-69%]. Hands were more likely to be contaminated with E. coli in low/lower-middle-income countries (prevalence: 49% [25% - 72%]) than in upper-middle/high-income countries (6% [1% - 12%]). In low/lower-middle income countries, E. coli prevalence was higher in urban compared to rural settings (52% mean prevalence in urban versus 33% in rural), although substantial heterogeneity between studies limited confidence in this finding. The review also highlighted the importance of standardizing hand sampling methods, as hand rinsing was associated with greater fecal contamination compared to other sampling methods.